Tamping machine



M, 197 G. H. BROWN 3,303,728

TAMPING MACHINE Filed Aug. 28, 1964 l NVENTOR.

j: 2 65mm) H. eeowu United States Patent 3,308,728 TAMPING MACHINE Gerald H. Brown, 870 N. 20th St., Columbus, Ohio 43219 Filed Aug. 28, 1964, Ser. No. 392,890 7 Claims. (Cl. 9448) This invention relates to a tamping machine and has as an object the provision of a simple rugged and efficient tamping machine requiring a minimum number of parts.

Another object of this invention is to provide a tamping machine having a long useful life and operating at a relatively low noise level.

A further object of this invention is the provision of a tamping machine which may be easily and quickly disassembled for repairs.

Other objects and advantages reside in the construction of parts, the combination thereof, the method of manufacture and the mode of operation as Will become more apparent from the following description.

Referring to the drawings:

FIGURE 1 is a perspective view of a tamping machine made in accordance with this invention.

FIGURE 2 is a cross-sectional view as viewed in the direction of arrows 2-2 of FIGURE 1.

FIGURE 3 is a cross-sectional view taken along line 3.3 of FIGURE 2.

Referring to the drawings in greater detail, the tamping machine is generally indicated by the reference character and includes an upper housing portion 12 and a lower housing portion 14. The lower housing portion 14 includes a generally vertically oriented hollow tamping tube 16 having a shield mounting plate 18 welded to the base thereof. A tamping shoe 20 having aligning webs 22 is afiixed to the plate 18 as by mounting bolts 24. Those skilled in the art will appreciate that the shoe 20 is inclined relative to the tamping tube 16 so that the tamping machine 10 moves forward as the shoe 20 vibrates. The mechanism causing the shoe 20 to vibrate will be described in detail below. Affixed to the top of the tamping tube 16 is a mounting or connecting plate 26 for the lower housing portion 14. The plate 26 has an aperture 28 therein coextensive with the internal dimensions of the tamping tube 16.

Mounted on top of the plate 26 is a support block 30 for a pair of bearing members 32 in which is journalled a crank shaft 34 for rotation about a generally horizontal axis. The crank shaft 34 drives a crank arm 36 having a crank pin 38 projecting therefrom centrally over the tamping tube :16. Rotatably confined on the crank pin 38 as by a nut 40 is an upper sleeve 42 of a connecting rod 44 which, when the crank arm 36 is in its lowermost position as illustrated in FIGURE 3, extends along the vertical center line or axis of the tamping tube 16. A weight block 46 having a pair of upwardly projecting apertured lugs 48 is suspended within the tamping tube 16 by means of a pin or bolt 50 passing through the apertures in the lugs 48 and received within a lower sleeve 52 of the connecting rod 44. As will be apparent below, the weight block 46 is adapted to slide within the tube 16 and its cross-sectional configuration is the same as, but smaller than, the internal cross-sectional configuration of the tamping tube 16.

The crank shaft 34 is driven by any suitable motor such as the two-cycle gasoline engine 54, which is mounted on top of the upper housing portion 12 by a mounting 3,308,728 Patented Mar. 14, 1967 bracket 56. The crank shaft 34 and motor 54 are con nected by a speed reduction transmission system illustrated herein as comprising a drive pulley 58 afiixed to the free end of a motor drive shaft 60, a driven pulley 62 mounted on the end of the crank shaft 34 opposite from the crank arm 36, and a compound idler pulley 64 drivingly connected to the pulleys 58 and 62 by drive belts 66.

The pulleys 62 and 64 and the belts 66 are enclosed Within a pulley housing including a vertical, upper shield plate 68 welded to the rear side of the upper housing portion 12. As illustrated in FIGURES 1 and 2, the upper shield plate 68 projects upwardly above the top of the upper housing portion 12 and may be wider than the upper housing portion 12 to accommodate relatively large pulleys. A vertical, lower shield plate 70 is welded or otherwise connected to the rearward edge of the plate 26 of the lower housing portion 14 with its top edge abutting the bottom edge of the upper shield plate 68. The pulley housing also includes a cover plate 94 releasably aifixed to the edges of the shield plates 68 and 70 in any suitable fashion.

Apertures 72 and 74 are located within the upper shield plate 68 for the shafts 60 and 34, respectively. The lower shield plate 70 is apertured at 76 to receive an idler pulley shaft 78 which is journalled for rotation Within a bearing plate 80 that is adjustably mounted on a pulley mounting plate 82. The pulley mounting plate 82 may be welded or otherwise suitably afiixed to the exposed face of the lower shield plate 70. The bearing plate 80 has a forwardly extending flange 84 thereon which has a threaded aperture receiving an adjusting screw 86 passing through a fixed plate 88 Welded to the tamping tube 16 and the lower shield plate 70. By loosening a pair of nuts 90 which secured the plates 80 and 82 together and then changing the position of flange 84 relative to the adjusting screw 86, the position of the idler pulley shaft 78 can be changed and, hence, the tension on the belts 66 can be varied.

The upper housing portion 12, which is shaped as a bonnet or cowl overlying the crank assembly 34, 36 and 38, has a generally rectangular flange 96 extending around its base releasably connected to the plate 26 as by bolts 98. It is thus seen that the housing for the tamping machine 10 may easily be disassembled by removal of the pulley cover plate 94 and removal of the belts 66, and finally, by removal of the bolts 98 whereby the upper housing portion :12 may be removed from the lower housing portion 14. Along with the upper housing portion 12, of course, will be removed the upper shield plate 68 while the lower shield plate 70 welded to the plate 26 remains therewith. Thus, shoud any part of the mechanism located within the tamping machine housing be in need of repair, such repairs can quickly and conveniently be made.

The tamping machine is held and guided by a handle structure including a pair of vertical handle members 100 connected at their lower ends to opposite sides of the upper housing portion 12 and connected at their upper ends to a generally oval-shaped, horizontal handle member 102 which, as illustrated in FIGURE 2, may be made from hollow tubing and to which a handle bar 104 is connected. Suitable shock mounts, which may be entirely conventional, are placed at the joints between the vertical handle members 100 and the horizontal member 102, and also between the vertical handle members 100 and the upper housing portion 12. The upper shock mounts are designated 106 and the lower shock mounts are designated 108. Since these form no part of the invention, they are not described in detail herein. Their function is to provide resiliency between the handle bar 104 and the housing portions 12 and 14. A gas tank 110 for the engine 54, along with motor controls (not shown), may be mounted upon the horizontal handle member 102.

As apparent from the foregoing description, the tamping machine is caused to vibrate by movement of the weight block 46 within the tamping tube 16. The throw of the crank arm 36 and the connecting rod 44 is sulficiently short that the weight block 46 never contacts the shield mounting plate 18. Hence, in this device, there is no hammering of the tamping shoe as is conventional in tamping machines. The reciprocating movement of the weight block 46 within the tamping tube 16 creates a vibratory tamping action sufficient for most tamping operations. Machines made in accordance with this invention are successfully being used having an overall weight of 110 pounds utilizing a weight block Weighing 32 pounds and having a crank shaft 34 driven at speeds ranging from 200 to 700 revolutions per minute.

The weight block 46 is guided for sliding movement within the tamping tube 16 by bearing assemblies comprising elongate, vertically oriented wear strips 112 mounted on the inner faces of the tamping tube 16 and bearing pads 114 mounted in sockets bored within the side faces of the weight block 46. As illustrated in FIG- URE 3, coil springs 116 located in the bearing pad receiving sockets bias at least some of the bearing pads 114 outwardly to insure contact of the bearing pads 114 with the wear strips 112. Desirably, there are two bearing pads 114, one spaced above the other, in each face of the Weight block 46 and the springs 116 should be located in one side of each pair of opposite sides of the weight block 46. Of course, there could be springs 116 biasing each of the bearing pads 114 outwardly.

To minimize the noise associated with the operation of the tamping machine and to increase the useful life of the machine, the bearing assemblies 112 and 114 are located, as shown best in FIGURES '2 and 3, in such manner 'as to minimize the wear on each of the bearing assemblies. As the crank shaft 34 rotates, the connecting rod 44 will oscillate in a vertical plane which is perpendicular to that vertical plane occupied by the center line of the crank shaft 34. This oscillation of the connecting rod 44 tends to cause the weight block 46 to be oscillated from side-to-side within the tamping tube 16. A bearing surface lying in the vertical plane in which the center line of the connecting rod 44 oscillates would receive the full force of the oscillation of the weight block 46. To reduce the attendant noise and wear of the bearings, the bearing assemblies 112 and 114 are located so that two of the bearing assemblies are equally spaced on each side of the vertical plane in which the center line of the connecting rod 44 oscillates, whereby two'bearing assemblies share the force of the aforementioned oscillations of the weight block 46.

As illustrated in FIGURE 3 wherein the tamping tube .16 is square inhorizontal cross-section as is the weight block 46, the vertical plane occupied by the crank shaft 34 extends across one diagonal of the square cross-sectional areas of the tamping tube 16 and the block 46. Accordingly, the vertical plane in which the center line of the connecting rod 44 oscillates extends across the other diagonal. The wear strips 112 are positioned centrally of the'internal faces of the tamping tube 16 and the bearing pads 114 centrally of the faces of the weight block 46. This symmetrical array of the hearing assemblies 112 and 114 on opposite sides of the two aforedescribed vertical planes has been found to greatly increase the useful life and reduce the operating noise of machines of this type because two adjacent bearing assemblies 112 and 114 share the load of the oscillation of the weight block 46., Also, there may be some wedging of the corners of the weight block 46 between adjacent bearing assemblies 112 and 114, which minimizes the oscillation of the weight block 46.

Although the weight block 46 is illustrated as being square in horizontal cross-section, the block 46 could be shaped differently. For example, the block 46 could be generally cylindrical and, therefore, appear circular in horizontal cross-section. If so designed, the wear strips 112 would be located on diametrically opposed portions of the tamping tube 16, and would be placed in a symmetrical array on opposite sides of the aforedescribed vertical planes containing, respectively, the axis of rotation of the crank shaft 34 and the center line of the connecting rod 44.

Although the presently preferred embodiment of the device has been described, it will be understood that within the purview of this invention various changes may be made in the form, details, proportion and arrangement of parts, the combination thereof and mode of operation, which generally stated consist in a device capable of carrying out the objects set forth, as disclosed and defined in the appended claims.

Having thus described my invention, 1 claim:

1. A tamping machine comprising: a housing having a generally vertically oriented tamping tube, a tamping shoe mounted on the bottom of said tamping tube, a weight block slidable within said tamping tube, a crank arm, drive means rotating said crank arm about a generally horizontal axis lying in first vertical plane, a connecting rod interconecting said crank arm and said weight block, the vertical center line of said rod oscillating in in a second vertical plane perpendicular to said first vertical plane, and two pairs of bearing assemblies disposed between said weight block and said tamping tube on opposite sides of said first vertical plane, the two bearing assemblies of each of said pairs being disposed on opposite sides of said second vertical plane.

2. The structure of claim 1 wherein each of said bearing assemblies comprises an elongate wear strip affixed to said tamping tube and a bearing pad carried by said Weight block having a surface slida-bly engaged with said wear strip. 7

3. The structure of claim 2 wherein bias means bias at least some'of said bearing pads into engagement with said wear strips.

4. A tamping machine'compn'sing: a housing having a generally vertically oriented tamping tube; a Weight block; a crank arm supported in said housing above said tamping tube for rotation about a horizontal axis, a connecting rod connecting said weight block to said crank arm and suspending said weight block for sliding movement within said tamping tube, drive means rotating said crank arm about said axis and thereby reciprocating said weight block vertically within said tamping tube whereby said tamping tube is caused to vibrate; a tamping shoe afi'ixed to the bottom of said tamping tube and vibrating therewith; at least two pairs of elongated wear strips extending vertically along a substantially length of said tamping tube on inner face thereof; a plurality of bearing surfaces, at least one for each wear strip, projecting externally of said weight block and slidably engaged with said wear strips, said pairs of Wear strips and hearing surfaces being disposed symmertically about the vertical plane containing said axis and on opposite sides thereof.

5. The structure of claim 4 wherein the interior of said tamping tube is square in horizontal cross-section, said axis lying diagonally across said square cross-section, and said wear strips are located centrally of the interior faces of said. tamping tube.

6. A tamping machine comprising: an upper housing portion and a lower housing portion, said lower housing portion including a vertical, hollow tamping tube, a tamping shoe connected to the bottom of said tamping tube, said upper housing portion overlying said lower housing portion, a crank assembly supported by said lower housing portion within said upper housing portion, a weight block suspended by said crank assembly within said tarnping tube, drive means at least partially supported by said upper housing portion and drivingly engaged with said crank assembly, and removable fastening elements interconnecting said upper and lower housing portions whereby said upper and lower housing portions may be disconnected to expose said crank assembly and said weight block.

7. The structure of claim 6 wherein said drive means includes a plurality of belt-driven pulleys projecting beyond adjacent sidewalls of said upper and lower housing portions and cover means are provided for said pulleys.

References Cited by the Examiner UNITED STATES PATENTS 2,845,050 7/ 1958 Wacker. 3,073,219 1/1963 Miller 9448 3,090,286 5/1963 Kestel 9448 3,199,424 8/1965 Glass 9448 FOREIGN PATENTS 730,592 5/ 1955 Great Britain.

JACOB L, NACKENOFF, Primary Examiner. 

1. A TAMPING MACHINE COMPRISING: A HOUSING HAVING A GENERALLY VERTICALLY ORIENTED TAMPING TUBE, A TAMPING SHOE MOUNTED ON THE BOTTOM OF SAID TAMPING TUBE, A WEIGHT BLOCK SLIDABLE WITHIN SAID TAMPING TUBE, A CRANK ARM, DRIVE MEANS ROTATING SAID CRANK ARM ABOUT A GENERALLY HORIZONTAL AXIS LYING IN FIRST VERTICAL PLANE, A CONNECTING ROD INTERCONECTING SAID CRANK ARM AND SAID WEIGHT BLOCK, THE VERTICAL CENTER LINE OF SAID ROD OSCILLATING IN IN A SECOND VERTICAL PLANE PERPENDICULAR TO SAID FIRST VERTICAL PLANE, AND TWO PAIRS OF BEARING ASSEMBLIES DISPOSED BETWEEN SAID WEIGHT BLOCK AND SAID TAMPING TUBE ON OPPOSITE SIDES OF SAID FIRST VERTICAL PLANE, THE TWO BEARING ASSEMBLIES OF EACH OF SAID PAIRS BEING DISPOSED ON OPPOSITE SIDES OF SAID SECOND VERTICAL PLANE. 